Just inside the 12th-century church of St Mary’s, Iffley, near Oxford, a 21st-century stained-glass window radiates colour, beauty and a thrilling interpretation of the Crucifixion: The Flowering Tree. Christ hangs from an abundantly blossoming tree on a green hill, from which the river of life flows sinuously through green fields. Life is everywhere, from the sheep clustered at the foot of the tree to the fish in the river and the rabbits in the fritillary-studded meadows. Life — unimagineable and eternal — is what Jesus gave us through his death on the cross, and this is the aspect of the Crucifixion leading directly to Resurrection that the artist Roger Wagner chose to celebrate.Wagner, who is known primarily for his paintings, had never worked in glass before he received the commission from his own parish church. He learned stained glass making from scratch, and not surprisingly spent a year of his life on the work. Such diligence and dedication to the craft that underlies true art are typical of the man, as was his sensitivity to the work’s setting. The Flowering Tree complements a window of the Nativity by John Piper, joyous, colourful and very English: Piper draws on the old tradition that on Christmas Eve the animals can speak, and here a cockerel, a duck, a goose and some sheep tell of Christ’s birth in comical Latin. Wagner’s River of Life points towards the baptismal font that stands between the two windows.

Tradition is important to Wagner, as guide and inspiration drawn from the great cloud of witnesses who preceded him in the Western canon. But, unusually, he had thought his Flowering Tree an original concept — until he visited the Roman church of San Clemente in Laterano and saw a 12th-century mosaic version in the apse. Here Christ hangs on a crucifix sprouting leaves, with the river running down to succour deer, sheep and wildfowl. “As a hind yearns for rivers of water, so mysoul yearns for you Oh God,” as the psalmist put it (in Wagner’s own translation).

“I’ve never been more astonished” said Wagner. “I thought I’d been completely original, but I found they’d anticipated me by a thousand years.”

Roger Wagner’s father was Sir Anthony Wagner, Garter Principal King of Arms, the senior herald of the College of Arms, and he grew up in an atmosphere where tradition was a living force. On an early family holiday, he was deeply impressed by Fra Angelico’s frescoes in the monastic cells at San Marco in Florence: he had not thought it possible to depict biblical scenes so naturalistically.

After reading English at Oxford, he studied art at the Royal Academy Schools. His determination to learn 16th-century painting techniques puzzled one of his tutors: wasn’t it like a contemporary dramatist trying to write in blank verse?

The answer, of course, is that it depends what the artist or dramatist does with the technique: it is vital to avoid mere pastiche.“The Flowering Tree” at St Mary’s, Iffley.

Wagner was acutely aware of the challenges that have faced Christian artists since the beginning of the 20th century. Cezanne, who held true to the great tradition of Western art, had said: “I take my painting and place it next to a God-made object like a tree or a flower, and if it clashes it is not art.” But for Picasso and Braque, Cezanne’s immediate successors, the clash between a cubist work and a God-made object was deliberate. Ever since there has been, at least at the cutting edge of modernism, a tendency to disdain the past, setting up an apparent opposition with the tendency of all religions to look backwards at their own narratives. But, as Wagner says, if you scrape away the “surface froth” of progressive art theory, the energy, invention, techniques and playfulness of modernism are as available to religious artists as to anyone else.

He was equipped with faith, talent and growing technique. But he needed to find a style, and perhaps more importantly a forum. Clearly, his work would never be considered for the Turner Prize. Challenged to remain true to the modern world, in the early 1980s he painted and printed extensive scenes of the old industrial East End of London before the docklands redevelopment took hold. Some of the woodcuts made their way into In A Strange Land, a hand-printed translation, by Wagner, of Psalm 137: “By the waters of Babylon, we sat down and wept . . . How shall we sing the Lord’s song in a strange land?” There followed a remarkable series of painted landscapes of industrial decay with their implied human suffering — and, always, the promise of redemption through Christ’s sacrifice.

Steeped in the Bible, Wagner holds the Jewish people, the first to hear the word of God, in special reverence. On his regular train journeys between Oxford and London, the looming presence of the Didcot power station impressed itself on his consciousness. One day he saw a huge umbrella-shaped cloud condensing and tumbling over the six cooling towers and one tall chimney, and an idea began to form. First came Surely He Has Born Our Griefs (1989), a deposition scene, with the mourners round Christ’s body wearing concentration camp stripes and the star of David.

Four years later he painted Menorah — the Didcot plant interpreted as the seven-branched candlestick which burned eternally in the Jerusalem temple before its destruction. The three crucifixes are set before the Didcot towers which belch smoke as if they were the ovens of Auschwitz. In the foreground, bathed in apocalyptic light, grief-stricken Jews comfort each other. Menorah was acquired by the Ashmolean Museum in Oxford and is currently on public view at St Giles’ Church nearby.

Wagner’s most influential — certainly his most reproduced — painting may be The Harvest is the End of the World and the Reapers Are Angels. The eschatological scene has a powerful effect on most viewers, struck by its matter-of-fact immediacy: the end is not just nigh, it is happening because God has sent his angels to make it happen. The title comes from chapter 13 of St Matthew’s Gospel, where Jesus explains the parable of the tares (or darnel) to his disciples:

He that soweth the good seed is the Son of man; The field is the world; the good seed are the children of the kingdom; but the tares are the children of the wicked one; The enemy that sowed them is the devil; the harvest is the end of the world; and the reapers are the angels. As therefore the tares are gathered and burned in the fire; so shall it be in the end of this world.

The theme first occurred to him when still an undergraduate. In one of his Fire Sonnets, published in 1984, Wagner wrote:

I saw the cherubim one summer’s nightReaping, it seemed, a field of endless wheatI heard their voices through the fading lightWild, strange and yet intolerably sweet.

Stylistically, The Harvest shows the influence of Samuel Palmer, but achieves an effect that is all Wagner’s own, especially the subtle geometrical composition. In bright late afternoon light slanting across a cornfield framed by an oak tree and sycamores, three angels are devotedly scything, raking and gathering sheaves. They are utterly intent on their work. In the middle distance more angels are at work on the next field, while the sky beyond is already dark and thunderclouds are forming. It is at once deeply mysterious and shockingly clear.

While continuing to paint over the next 20 years, Wagner’s deep biblical reading, his poetry, scholarship and gift for languages were also combined in The Book of Praises, an edition of the Psalms. He taught himself Hebrew in order to make his own translation, and the three volumes (of five) so far published were hand printed. Each psalm is presented in parallel English and Hebrew text and illustrated with wood engravings and, in the second and third volumes, small jewel-like paintings.

Some directly illustrate subjects or scenes within the particular psalm, while others are more allusive. Psalm 60 contains the line beloved of generations of schoolchildren “Moab is my wash-pot”; but Wagner chose the next verse “To Edom I cast my sandal,” and painted a view of the lower Jordan valley dominated by an enormous angel looming over the horizon, the cast sandal spinning towards the viewer. By contrast in Psalm 61, a grief-stricken exile acknowledges God as his refuge and prays, “Let me stay in your tent forever, taking refuge in the shelter of your wings.” Wagner illustrated this with a pastoral scene of Abraham sitting outside his tent with three winged angels, and Mount Lebanon in the background.

He had painted two scenes of Abraham and the angels (Genesis 18) some years earlier: one set in a Syrian landscape with a huge smoking cement works in the background, and a second in Minsmere, Suffolk, with the Sizewell nuclear power plant looming beneath a crescent moon.

Landscape is central to Wagner’s art. His parents had a cottage at Aldeburgh on the Suffolk coast, and this gentle low-lying country has always been important to him. But the Holy Land, which he visited in 1998, and Oxfordshire, where he lives, are also powerful presences in his work.

“It has always seemed natural to me to paint pictures in which contemporary landscapes and biblical stories occupy the same space,” Wagner said in a 2012 lecture, “Marching To An Antique Drum”. He observed that John Constable, a Suffolk man, saw landscape as God’s own work and was motivated to present it as truly and freshly as possible.

“Brightwell Barrow III”, 2012

His “pure” landscapes, without angels or obvious biblical narratives, are yet profoundly imbued with God’s presence. In 2012, for instance, he painted four large views of Brightwell Barrow in Oxfordshire, a conical hill near the Wittenham Clumps, so often drawn by Paul Nash. Each takes the same viewpoint, with a low hedge in the foreground framing the tree-topped hill beneath a huge energetic sky. The cloudscapes and light effects on the diagonal furrows of the hill vary radically across the four works. The high degree of formality suggests there is more going on here than a simple depiction of landscape. The unearthly light on trees seemingly poised between heaven and earth suggests the immanence of the divine. However one sees them, these stunning English landscapes are profoundly spiritual works.

Roger Wagner would be a remarkable artist in any age. He is a painter, printmaker, stained-glass maker, poet, art theorist and theologian. His work is informed by the great tradition of Western art, and depends to an uncommon degree on the crafts and skills developed over many centuries. Yet there is nothing old-fashioned about these paintings and prints. In the 21st century they speak to us directly of things that modern art largely ignores: beauty, our relationship with God, and God’s plan for the world.

T.S. Eliot is a strong influence on Wagner, and these lines from “Little Gidding” speak to his task in reconciling religious tradition with modernist art:

With the drawing of this Love and the voice of this CallingWe shall not cease from explorationAnd the end of all our exploringWill be to arrive where we startedAnd know the place for the first time.